Summary

Soil organic matter (SOM) balances can assist sustainable organic matter management. Still, existing methods need to be revised, especially when applied in organic farming. A basic problem is the linear concept which seemingly does not reflect the effective dynamic. Furthermore the relevance of SOM is dependent on the cultivation system and cultivation intensity, respectively. The importance of SOM as a nutrient source increases with diminishment of cultivation intensity, i.e. synthetic fertilizer application. Here turnover of organic matter becomes the key factor for nutrient supply. Correspondingly, a higher SOM reproduction level that promotes increased SOM content and/or turnover should be an objective in organic farming. Soil organic matter balances must therefore be adapted with regard to the coefficients as well as to target SOM reproduction levels.